Flickering flame essentially twisty (7)
I believe the answer is:
lambent
'flickering' is the definition.
(thesaurus)
'flame essentially twisty' is the wordplay.
'essentially' means to look at the middle letters.
'twisty' becomes 'bent'.
The middle letters of 'flame' are 'lam'.
'lam'+'bent'='LAMBENT'
(Other definitions for lambent that I've seen before include "Making stealthy moves" , "Glowing with a soft radiance" , "shedding some light" , "Flickering like malt, Ben" , "Of flame or light, playing about a surface" .)